関連する実験動画
Updated: Jul 3, 2026
08:15
Visualizing Oceanographic Data to Depict Long-term Changes in Phytoplankton
Published on: July 28, 2023
海洋無脊椎動物の世界的な多様性におけるファネロゾイク期の傾向
John Alroy1, Martin Aberhan, David J Bottjer
1National Center for Ecological Analysis and Synthesis, University of California-Santa Barbara, 735 State Street, Santa Barbara, CA 93101, USA. alroy@nceas.ucsb.edu
Science (New York, N.Y.)
|July 5, 2008
まとめ
海の無脊椎生物の多様性は,白亜紀中期以降,急激な放射線ではなく,控えめな上昇を示しています. 近代的な分析は,安定した地球規模と地域規模の富と,古生代と古新生代を通じて一貫した緯度グラデーションを明らかにしています.
科学分野:
- パレオントロジー・パレオントロジー
- マリン・バイオロジー マリン・バイオロジー
- 進化生物学の進化生物学について
背景:
- 以前の研究では,白亜紀と亜紀の間,海中の無脊椎動物の放射能が有意に増加していたことが示唆されていた.
- この認識されたパターンは,古い分析方法とデータセットに基づいていた.
研究 の 目的:
- 海洋無脊椎動物の多様化のパターンを,包括的な化石発生データセットを使用して再評価する.
- 以前に提案された急激な放射線が,現代の分析技術によって支持されているかどうかを判断する.
主な方法:
- 350万の化石の発生に関する新しいデータセットを利用した.
- サンプリングの標準化と分析のための堅固なカウント方法を採用しました.
- 古い分析プロトコルの結果を,新しい標準化された方法と比較した.
主要な成果:
- 急激な放射線パターンは,古い分析プロトコルを使用してのみ複製されます.
- サンプル採取の標準化と堅実なカウントによる分析は,クレタセウス中期以降の明確な傾向なしに,多様性のわずかな増加を明らかにしています.
- ネオゲン期の海洋無脊椎動物の多様性は,地球規模および地域的に,中期パレオゾイク期の2倍未満でした.
- グローバルとローカルの富の比率は比較的安定したままでした.
- 緯度の多様性の傾きは,初期のパレオゾーイクでも明らかでした.
結論:
- 海洋無脊椎動物の急激な放射線は,以前の分析方法の人工物である.
- 現代の厳格な分析は,海洋無脊椎動物の多様性のより穏やかな増加を示しています.
- 緯度の多様性パターンと,地球規模と地域の富の関係が,長い地質的時間尺度で安定している.
関連する概念動画
01:27Diversity of Protists III
Rhizaria are a diverse group of unicellular protists characterized by their threadlike cytoplasmic extensions known as pseudopodia. These structures aid in both locomotion and feeding, giving Rhizaria an amoeboid appearance. Their amoeboid morphology once led to taxonomic confusion, but molecular phylogenetics has clarified their evolutionary placement and emphasized their shared use of pseudopodia despite divergent lineages.This clade comprises diverse lineages such as Chlorarachniophyta,...
01:27Diversity of Protists IV
Amoebozoa represent a diverse group of terrestrial and aquatic protists that utilize lobe-shaped pseudopodia for locomotion and feeding. This characteristic differentiates them from the Rhizaria, which possess threadlike pseudopodia. The primary classifications within Amoebozoa include gymnamoebas, entamoebas, and the plasmodial and cellular slime molds. Phylogenetic evidence indicates that Amoebozoa diverged from a lineage that ultimately gave rise to fungi and animals.Gymnamoebas and...
01:27Diversity of Protists II
Alveolates are a group of organisms recognized by the presence of alveoli, which are cytoplasmic sacs located beneath the cell membrane. While their function remains uncertain, alveoli may help regulate water balance by controlling how much water enters and leaves the cell. In dinoflagellates, these structures may serve as armor plates. There are three major types of alveolates: ciliates, which move using cilia; dinoflagellates, which use flagella for movement; and apicomplexans, which are...
01:15Diversity of Protists I
Excavata is a diverse group of protists that includes both chemoorganotrophic and phototrophic species, with some thriving in anaerobic environments. Among the key groups within Excavata are diplomonads and parabasalids, which are flagellated protists that lack mitochondria and chloroplasts. These microorganisms typically inhabit anoxic environments, such as the intestines of animals, where they exist either symbiotically or as parasites, relying on fermentation for energy production. Some...
02:56The Fossil Record
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
01:24Diversity of Archaea II
Archaea, one of the three domains of life, exhibit remarkable diversity and adaptability, thriving in both extreme and moderate environments. Historically, most identified archaea have been classified into two major phyla: Euryarchaeota and Crenarchaeota. However, recent molecular studies have expanded this classification to include three additional phyla: Thaumarchaeota, Nanoarchaeota, and Korarchaeota, each exhibiting unique characteristics and ecological roles.Thaumarchaeota: Mesophiles...